1. Field of the Invention
The present invention relates to a two-component polyurethane/vinyl ester foam system with a polyol component, which contains at least one polyol, a catalyst for the reaction of the polyol with the polyisocyanate, at least one polymerizable vinyl monomer and water or a blowing agent on the basis of a compressed or liquefied gas as foam-forming agent, and a polyisocyanate component, which contains at least one polyisocyanate and a catalyst for the polymerization of the vinyl monomer. The present invention also relates to a method of using this hybrid foam system as a flame retardant material and material for filling openings, cable and pipe bushings in walls, floors and/or ceilings of buildings for the purpose of fire protection.
2. Description of the Prior Art
The use of polyurethane foam systems for forming the polymer matrix of polyurethane foams and fire protection products is well known. For example, it is customary to install, for example, doors and windows of buildings with the help of such a polyurethane foam in the appropriate openings of the building and to foam cable and pipe bushings in walls, floors and/or ceilings of buildings for the purpose of fire protection using such a polyurethane foam system, in order to prevent or delay flames penetrating through these openings in the case of a fire.
It is an essential task of the polymer matrix of such products, especially in the case of a fire-protection product, to act as a binder for the actual fire-retardant additives, such as an intumescing material based on an acid-forming agent, a carbon-supplying compound and a gas-forming agent, as well as expanding graphite or expandable phyllosilicates. The intumescing materials expand in the event of a fire, increase the volume of the foam and make the latter more fire resistant.
As a rule, the polyurethane foam systems, used for such purposes, comprise a polyol component and a polyisocyanate component, which, in the presence of a blowing agent such as water, react with one another with the formation of polyurethane foam. These polyurethane foams may be rigid or soft and these properties, as is well known to those of ordinary skill in the art, can readily be adjusted by appropriately modifying the formulation. In this connection, reference is made to D. Klempner et al., Polymeric Foams, Hanser Publishers, Munich (1991).
Adapting such polyurethane foam systems in the course of developing a foam formulation is, however, always costly if, for example, the formulation is to be converted from a rigid foam to a soft foam or vice versa, since the shrinkage behavior of soft foams is far more pronounced and is to be prevented.
Accordingly, an object of the present invention is to make available such polyurethane foam systems, which would differ only marginally from the formulation of a more rigid and a softer foam, so that the desired foam properties can be adjusted by a minor modification of the formulation depending on the customer's wishes or on the requirements of the application.